Ten Facts About Owls
Which Bird is Not Like the Others?
Earlier this week, an article was published in the journal Zootaxa announcing the discovery of a new species of bird that lives in the forests of Gabon, Africa. The article revealed various details about the size and coloration of the bird and in some instances the report sounded as if it were penned by a boasting parent:
"The brilliant orange ‘flame’ colored throat of this species outshines the others in the genus." (Schmidt 2008: 31)
As is often the case with the declaration of a new species, there was particular excitement surrounding the selection of the animal's name. This decision was announced in the report with no less enthusiasm:
"The combined Greek name is meant to describe: A stout/sturdy bird (Stiphrornis) that bears a flame colored throat (pyrrholaemus). Combined with the English common name of Olive-backed Forest Robin which highlights the distinctive olive back and rump, the bird is aptly described by its names." (Schmidt 2008: 31)
So there it is, the little newfound bird of Gabon's deep forest is the proud owner of the rather charming name: Olive-Backed Forest Robin (Stiphrornis pyrrholaemus).
Thus decorated with a well-contemplated name, the newly described bird soon received a warm welcome from the world's media as simply 'a new species of robin'. Such phrasing is not a surprising choice for a headline, since 'robin' is less of a tongue-twisting mouthful than 'Olive-Backed Forest Robin' or 'Stiphrornis pyrrholaemus'. These longer, more eloquent names can be buried with the lead so to speak, somewhere in the first several paragraphs (as I have done here).
Of course this is not to say that any of this is problematic: the bird is indeed a robin. Whatever a robin is. Most birdwatchers or avian enthusiasts may know better than me what the common name robin means. As far as I can tell, the name robin has been tossed around quite freely and simply means a bird with a red breast. Usually. Sometimes it is more orange than red.
Read more...What Are Xenarthrans?
Guam's Wildlife Threatened by Invasive Snake
Sometime shortly after the end of World War II, an unwelcome predator found its way to the island of Guam: the Brown Tree Snake (Boiga irregularis). There is no way to know exactly how or when the snake arrived on Guam. The most likely explanation is that after the war ended, snakes from the Admiralty Islands (located off the northwest coast of Papua New Guinea) repeatedly found their way onto US military cargo ships bound for the new US Pacific Headquarters on Guam.
When the stow-away snakes arrived on Guam, they found what to them must have been an island paradise. There were no predators on the island that could challenge them and there was an abundance of native fauna on which the invading snakes could prey: birds, mammals, and lizards. Guam’s native species had evolved in the absence of predatory snakes—the only snake species native to Guam is Ramphotyphlops braminus, a tiny, blind snake that feeds on arthropods. When coiled up, Ramphotyphlops braminus can fit on the top of a nickel. As a result, Guam’s local fauna was ill-prepared to cope with the aggressive, predatory 3–6-foot Brown Tree Snake.
The snakes’ presence went undetected until the early the 1950s, when people began noticing them around the Naval Port in central Guam. The snake population quickly expanded from there. By the early 1960s, the Brown Tree Snake had established itself over more than half of the island and by 1968, it had colonized all of Guam to varying degrees and densities.
Wherever the snakes went, populations of native birds crashed. A wave of bird disappearances spread out across the island following the path of the Brown Tree Snake. The snake's toll was particularly heavy on Guam’s forest-dwelling birds. Before the introduction of the brown tree snake, there were 11 native species of forest-dwelling birds on Guam. Today, nine of those species no longer survive on the island. A few species, such as the Guam Flycatcher and the Guam Rail, exist only in captivity.
The decline of Guam’s native occurred, for the most part, two and a half decades ago. But the ecological impact of the Brown Tree Snake does not stop there. A team of scientists from the University of Washington led by doctoral student Haldre Rogers have recently suggested that an onslaught of secondary ecological impacts brought on by the Brown Tree Snake are now surfacing.
Birds often play important roles within their communities and their presence in a habitat influences the flora around them by providing seed dispersal and insect control. If birds suddenly disappear from a community as they did 25 years ago on Guam, there may be significant vegetation changes that follow.
To find out if Guam’s forests are being impacted by the absence of native birds, Rogers and her colleagues set up numerous seed collection stations around False Elder (Premna obtusifolio) trees. They positioned seed collection stations directly beneath the canopy of the trees and also set up additional seed collection stations at distances of 3, 16, 33, and 65 feet from each study tree. They repeated this setup in two locations: Guam (where the Brown Tree Snake had extirpated most native birds) and Saipan (a nearby island that does not have Brown Tree Snakes).
After collecting seeds from their study stations, they found that on Saipan, seeds were dispersed outward from the tree. They found more seeds close to the tree and fewer further from the tree, but seeds were present in nearly all of the traps placed around the tree. On Guam, they seeds were present only in the traps that were located directly under the parent tree.
Rogers and her team also noticed another interesting difference between the seeds in the two study locations. The farther-dispersed seeds collected from trays on Saipan did not have seed coats. Rogers reasoned that these seed coats were removed as the seeds passed through the guts of the birds that dispersed the seeds. Such removal of the seed coat can facilitate germination. On Guam, because no birds were present to disperse the seeds, the seeds remained encapsulated in seed coats.
The story of the Brown Tree Snake and its impact on Guam’s wildlife is far from over. The snake has had an alarming impact on the islands birds and there is still much to learn about the after effects of this invasive snake’s arrival on the island.
References:
- Fritts, T.H., and D. Leasman-Tanner. 2001. The Brown Treesnake on Guam.
- Stricherz, V. 2008. Brown Tree Snake Could Mean Guam Will Lose More Than Its Birds. University of Washington.
Top: Photo © Isaac Chellman / University of Washington. Brown Tree Snake (Boiga irregularis). Bottom: Photo © Haldre Rogers / University of Washington. Over 100 traps like this one were placed under or near trees to collect information about seed dispersal on Guam and Saipan.
Scientists Track New England's Leatherback Turtles
A research team from the University of New Hampshire has tagged three wild Leatherback Turtles—one male and two females—as part of an effort to learn more about the species and to identify ways to better protect it. Each satellite tag, which costs about $5,000, is linked to a GPS system which transmits information about the turtle's activities and surroundings including swimming depth, water temperature, and location.
The Leatherback Turtle (Dermochelys coriacea) is not only the largest species of turtle alive today, it is the largest reptile on the planet. Adults can grow to lengths of 4 to 8 feet and weigh in the range of 700 to 2,000 pounds and they achieve these massive proportions on a diet of jellyfish.
Kara Dodge, a Ph.D. student at University of New Hampshire and leader of the research project, believes it is the pursuit of jellyfish that has brought increased numbers of Leatherback Turtles to the area. Dodge suggests that an abundance of jellyfish in New England's coastal waters has erupted due to elevated water temperatures and the Leatherbacks have gathered for a feast.
Little is known about the Leatherback's adult life. The western Atlantic populations of Leatherback Turtles nest on beaches in the Caribbean, northern South America, and southeastern Florida. Adult turtles migrate vast distances in pursuit of food. Their range is known to extend into the North Atlantic and from July through October are often seen in the waters off the coast of eastern Canada and New England.
The tagging project has already revealed some interesting results. The male Loggerhead Turtle, tagged on July 17 in Nantucket Sound has already been tracked a distance of 1100 kilometers. The two females, tagged on July 26 and 29 in Vineyard Sound, have traveled distances of 250 kilometers and 65 kilometers respectively.
The research team plans to continue tagging turtles in the region through September with the hopes of equipping a total of nine animals with tracking devices. The project is funded by the National Fish and Wildlife Foundation, the National Marine Fisheries Service Northeast Regional Office, and the Cape Cod Commercial Hook Fishermen's Association.
Find out more:
- UNH Researchers Tag First-Ever Free-Swimming Leatherback Turtles in New England (Eurekalert)
- The Leatherback Turtle (Turtle Trax)
- Leatherback Turtle Program (Large Pelagics Research Center)
- The Leatherback Trust
Top: Photo © Kara Dodge / UNH Large Pelagics Research Center. Mark Leach, captain of the F/V Sea Holly, poses with Henry. Bottom: Photo © Connie Merigo / New England Aquarium. Henry, the first free-swimming leatherback captured in New England waters, after he was tagged with a GPS-linked satellite tag by researchers from the University of New Hampshire's Large Pelagics Research Center.
Caribbean Reef Fish Fall Prey to Invading Lionfish
Scientists from Oregon State University report that coral reef communities throughout the Caribbean are being devastated by the invasive Lionfish. The predatory fish feeds on unsuspecting native fish with alarming efficiency. The study revealed that in a single 30-minute period, one adult Lionfish consumed 20 smaller fish. Additionally, within a five-week period, the Lionfish reduced the population of juvenile fish within the study plots by 79 percent.
The message is clear: shortly after Lionfish invade a reef, nearly 80 percent of the other reef fish species disappear. To compound the problem, many of the native fish that fall prey to Lionfish are herbivorous and feed on seaweed that otherwise crowds the reef. With many of the herbivorous fish gone, seaweed growth explodes, derailing the delicate balance of the reef.
The Lionfish is native to the tropical regions of the Pacific and Indian Oceans. In its home range, its numbers remain in check thanks to natural predators such as groupers. Also, prey fish in its native habitat are well adapted to eluding the Lionfish. But in the Atlantic, the Lionfish has few predators. Prey species are unfamiliar with the danger Lionfish pose to them.
Scientists suspect that Lionfish were introduced into the Atlantic Ocean in the waters off the coast of Florida in the early 1990s. They believe that individuals were released into the wild from aquariums or pet owners. Once released, the fish spread throughout the Caribbean. Populations also expanded northward along the eastern coastal waters of the United States. Lionfish have been recorded as far north as Rhode Island.
Find out more: Lionfish Decimating Other Tropical Fish Populations, Threaten Coral Reefs (Oregon State University)
Photo © Oregon State University. OSU researcher Mark Albins studying lionfish underwater.
Newborn Dolphins Are Active 24/7
Scientists have discovered that baby dolphins and infant orcas are insomniacs. The newborn cetaceans remain active around the clock for the first month of their lives. As a result, their mothers are deprived of sleep as well. Gradually, over the course of several months, the newborns and their mothers both increase their sleep time until they reach a normal level of sleep.
There may be significant advantages to young cetaceans that remain active for the first few weeks after birth. Constant activity may reduce the dangers posed by predators—by not sleeping, the young simply do not let their guard down. It may also help to maintain high body temperature until the young animal can pack on a sufficient layer of blubber. Additionally, the young cetaceans must surface more frequently than adults to breathe and staying awake all night may ensure they are better able to surface as much as is needed. Finally, the extended period of wakefullness may enable the young cetaceans a period of rapid growth and development.
Dr. Jerome Siegel, professor-in-residence at the Semel Institute for Neuroscience and Human Behavior at UCLA and chief of neurobiology research at the VA Greater Los Angeles Healthcare System described the findings and their implications:
"Somehow these seafaring mammals have found a way to cope with sleep deprivation, facilitating rather than hindering a crucial phase of development for their offspring. Their bodies have found a way to cope, offering evidence that sleep isn't necessary for development and raising the question of whether humans and other mammals have untapped physiological potential for coping without sleep."
The research project was conducted by a group of neuroscientists from UCLA and the VA Greater Los Angeles Health Care System. The team observed two adult female killer whales and their calves and four dolphins and their calves; all of the animals that were studied were observed in captivity.
Find out more: Behavioral Aspects of Sleep in Bottlenose Dolphin Mothers and Their Calves (UCLA)
Photo © Debra McGuire / iStockphoto.
Newfound Coral Reefs Off Brazilian Coast
Scientists working off the coast of Bahia state in Brazil have discovered a vast region of previously unknown coral reefs. Surprisingly, the newly discovered reefs are not located in remote waters. Instead, they are nestled up against the South Atlantic's largest known coral reef system: the Abrolhos reef system. Despite their proximity to the well-known Abrolhos reefs, the newly discovered reefs are concealed in deeper waters and are therefore quite inaccessible. Scientists relied on side scan sonar (a type of sonar frequently used to create nautical charts) to construct a map of the newfound reefs.
The research team that made the discovery of the new reefs included scientists from Conservation International, the Federal University of Espirito Santo, and Federal University of Bahia. They
The previously known Abrolhos reef system consists of a collection of coral reefs, volcanic islands, and sandy shoals that are scattered over nearly 6,000 square kilometers. The islands in the Abrolhos region are referred to as the Abrolhos Archipelago and include Santa Barbara Island, Redonda Island, Sueste Island, Siriba Island, and Guarita Island. These islands are surrounded by fringing reefs. The Abrolhos reef system also includes two archs of reefs, the Coastal Arc and the Outer Arc. The newly discovered reefs nearly double the size of the existing Abrolhos reef system.
The Abrolhos reef system is ecologically unique. It is home to a wealth of marine animals—corals, mollusks, and fish—found nowhere else in the world. The endemic coral species Mussismilia braziliensis is the main reef building coral within the Abrolhos reef system. Additionally, the structure of the Abrolhos reef is quite different from reefs found in the Caribbean and Pacific Ocean. Some regions of the reef consist of large mushroom-shaped coral formations know as chapeiroes. In some areas of the Abrolhos, the tops of the chapeiroes grow together and form bank reefs that span distances of between 1 and 20 kilometers.
Find out more:
- Scientists Discover New Reefs Teeming with Marine Life in Brazil (Eurekalert)
- Abrolhos: The South Atlantic's Largest Coral Reef Complex (SIGEP)
- Coral Reefs of the Abrolhos Bank, Brazil (Conservation International)
- Coral Reefs Dense with Unusual Wildlife (Treehugger)
Photo © RB Francini-Filho / Conservation International.
Why Are Native Fish Declining in the Colorado River?
Numerous native fish species of the Colorado River (such as Razorback Sucker, Roundtail Chub, Humpback Chub, Bonytail Chub, and Pikeminnow) have suffered significant declines over recent decades. During that same time period, non-native fish species (such as Rainbow Trout, Brown Trout, Striped Bass, Bluegill, and Crappies) have thrived. A team of scientists from Northern Arizona University led by Dr. Alice Gibb has been seeking to explain these trends and establish a set of recommendations on how to better protect the Colorado River's native fish species.
The researchers started their investigations in the laboratory environment. They first compared the escape responses of native and non-native fish species—they wanted to find out how successful each species was at escaping predators. Their observations revealed that native fish were at a clear disadvantage when compared to non-native fish. The larvae of native fish were less developed than non-native fish when they hatched. As a result, the native fish lacked the agility and morphological development needed to avoid predation. Non-native fish on the other hand were more mature when they hatched. Not only could they escape predators more efficiently than native fish, they also were capable of preying on native fish larvae.
Dr. Gibb and her colleagues then looked to the Colorado River: what conditions in the river made native fishes so vulnerable? To answer this question, they first considered the effects of the damming of the Colorado River. Before the Colorado River was dammed, there were fast moving currents. Turbulent water churned up sediment and plankton, making it easier for the larvae of native species to hide from predators and find food. Water temperatures were higher. After the river was dammed, fast moving water was replaced with lakes: water temperature fell and plankton settled. The larvae of native fish were left exposed as sediments were no longer churned up in the still lake water.
The research team suggests that to reverse the decline of native species in the Colorado River, management efforts must focus on removing non-native predators and reintroducing high-flow, turblent, sediment rich waters into the Colorado.
Find out more: River Damming Leads to Dramatic Decline in Native Fish Numbers (Science Daily)
Top: Photo © Alice Gibb / Northern Arizona University. Roundtail chub, Gila elegans, in the Gibb Laboratory at Northern Arizona University. Bottom: Photo © David Ward / Arizona Game and Fish. Confluence of Little Colorado River and Colorado River in the Grand Canyon.
Survey of Las Perlas Archipelago Reveals Rich Coral Diversity
A research team from the Smithsonian Tropical Research Institute has completed a survey of coral biodiversity in the Las Perlas Islands. Their study revealed a broad mix of coral species in the waters of Las Perlas. In total, they counted 57 species of corals (19 species of hard corals and 38 species of soft corals). They found that reefs in the region were small and patchy and some corals grew directly on bedrock on the sea floor instead of building layer upon layer of corals.
The survey showed that species diversity was highest in the waters surrounding the following islands:
- Isla Galera
- Isla San Telmo
- Isla Camote
- Isla Monte
- Bajo Trollope
- Isla San Jose
- Isla Pedro Gonzalez
Las Perlas, or the 'Pearl Islands', are located in the Gulf of Panama and together form an archipelago of more than 250 rocky islets. In May 2007, the Panama Government classified Las Perlas and their surrounding waters as a Marine Special Management Zone. As such, the region plays a key part in a larger conservation corridor that stretches from Costa Rica to Ecuador. Within the Las Perlas management zone, fishing is strictly regulated. Unfortunately, no restrictions are yet imposed on tourism and land development. Thus the Las Perlas reefs remains vulnerable to sedimentation, pollution, and coastal development.
To best protect this delicate ecosystem, the survey team calls for the establishment of "no-take" zones where fishing is strictly prohibited as well as the creation of a number of fully-protected marine reserves in regions of greatest species diversity. The team also suggests that further research should be carried out, which examines the movement and dispersal of marine organisms throughout the region.
Find out more:
- Protecting the Las Perlas Archipelago of Pacific Panama (Darwin Initiative)
- Panama Designates Las Perlas Archipelago Special Management Zone (STRI)
- Smithsonian Coral Biodiversity Survey of Panama's Pearl Islands (EurekAlert)
Photo © Edgardo Ochoa / STRI. Coral research in Las Perlas Islands, Panama.